A Foreign Country by Charles Cumming

Six months
before she is due to take up her position as the first female head
of MI6, Amelia Levene vanishes. Former MI6 officer Thomas Kell is
called out of retirement to find her. Was she kidnapped? Or
could Britain's most senior spy have defected? Approached by MI6 at
university, Cumming vividly showcases meticulous research and
insight into the undercover life of spies.